Apparatus and method for converting starch



Feb. 21, 1939. ;R. A. GALE I APPARATUS AND METHOD FOR CONVERTiNG STARCH Filpd May 20, 1937 2 Shet s-Shept 1 v INVENTOR. Rwland H. Gale Feb. 21, 1939. N R. A. 45m: 2,148.016

I APFARATUS AND METHOD FOR CONVERTING STARCH Filed May 20, 1937 2 Shaets-Shet 2- m 3 [I] a, 8

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n I b w v INVENTOR. BY Rowland (LGale ATTO Patented Feb. 21, 1939 UNITED STATES 4 APPARATUS AND METHOD FOR CONVERTING: STARE Rowland a. Gale, New York, n. Y.

Application May 269, 1937, Serial No. 143,689

5i Claims. it'll. 127-28) 7 This invention relates to improvements in apparatus and continuous methods for converting starch and similar materials.

The detailed objects of this invention will be 5 apparent from the following description when taken in connection with the attached drawings.

This invention resides substantially in the combination, construction, arrangement, rela tive location of parts, steps, and series of steps, 10. all in accordance with this disclosure.

In the accompanying drawings,

Figure 1 is a side 'elevational view with some parts in section 01' an apparatus suitable for practicing the method herein disclosed;

1a Figure 2 new plan view thereof with some parts broken away; and

Figure 3 is a cross-sectional view taken on the line 3-3 of Figure i.

In accordance with present practice, the cooking, digesting or converting of aqueous suspensions of starch and similar materials for use in the manufacture of textiles, paper, adhesives, foodproducts, beverages, and the like, is accomplished in several ways. These methods, which may be termed batch methods, have a number of undesirable inherent characteristics which in a general sense it is the object of this invention to obviate.

In accordance with one commonly employed method, starch, together with an enzyme, or other converting agent, is mixed in cold water in a large tub or vat. The contents are then heated to the desired temperature to permit the digestive action to proceed, which when completed is arrested either by the addition of chemicals or an increase in temperature in the batch. A second method, often employed, consists in pouring I a mixture of starch, with the addition of an enzyme or other converting agent, and cold water into a tank 01 water, the temperature of which is maintained assrigidly as possible at the point required for digestion. as,

Aside from the fact that both methods are batch methods, there are additional undesired characteristics which will now be explained. In the conversion of starch by the first method, the temperature is gradually raised by the introduction of steam into the vat. Considerable time is required. to raise the temperature of a large batch of this type to the desired reacting point, with the result that portions of the batch reach that temperature ahead of other portions so that conversion or digestion of some of the particles begins before others reach the gelatinizing 58 point. In addition, some of the granules natuparticles.

siderable difliculty is encountered, as a practical rally gelatinize more rapidly than others and are. consequently, acted upon by the enzymes or other converting agent sooner and or av longer period of time than are theless easily gelatiniaed At or near the gelatinizing temperature a considerable amount of starch is unavoidably converted by the converting agent to sugar or dextrine. For many purposes conversion of starch to sugar and dextrlne is undesirable and this objection is overcome to a considerable de- 10 gree by the second method of cooking mentioned above.

, The dlmculty with the second method is found in maintaining the temperature of the hot water into which the cold mixture is poured. In the first place, the starch mixture must be added slowly so as to permit the first portions. added to liqueiy or thin out and to allow for a continuous readjustment oi the temperature. As with the first method, part oi the starch is unavoidably acted upon, as will be obvious, for a longer period of time than those parts which are subsequently added. It is apparent that by either method it is, impossible to convert starch, with or without enzymes, so that all granules are acted upon equally for the same period of time and at the same temperature.

Aside from the variations in the treatment of diilerent portions of the same batch, it is also quite clear that as between different batches con- 30 matter, in producing continuously a uniform product.

An object of this invention is to eiiminate the batch method of conversion and to replace it 4 by a continuous process in which the individual particles or granules are acted upon to the same grammatically animproved form of apparatus suitable for carrying-out the continuous method hereof. At I is shown the mixing tank in which the water suspenson .is prepared. It is provided with a series of mixing paddles or be'aters 3 which are rotated by means of a motor 2. From the bottom of the tank lextends a discharge spout l positioned so as to deliver the cold water suspension of starch into a receptacle 5. The level of the water suspension may be maintained in the receptacle 5 by reason of a float B which is supported for vertical movement in a bracket 1 mounted on the top of the receptacle 5 and connected at its upper end by means of a link 3 to a valve '3 in the discharge spout 4.

The receptacle 3 forms part of a tunnel or tube 10 which, as is clear from Figure l, is not horizontal' but has a slight incline upwardly away from the receptacle 5. Journaled in this tube is a shaft I i upon which is mounted a series of heaters and propellers l2 which are constructed of a form as indicated so as not only to act to maintain the mixture uniform but to advance it towards the uphill end of the tube. A motor I3 is connected to the shaft II to effect rotation of the paddles. At the low point of the tube III is a discharge outlet ll provided witha' valve l5.

At It is a steam supply line provided with the branches I1, I 8 and 13, in which are connected the automatic valves 20, 2| and 22, respectively. .At 23, Hand 23 are temperature responsive devices, such as thermostatic bulbs, which-are connected by the pipes 23, 24 and 25, respectively, to

the valves 20, 2| and 22. As will be apparentto those skilled in the art, this provides an automatic method of controlling the steam flowing through the branches l1, l3 and I3. For example, the

valves 20, 2| and 22 may be of the diaphragm operated type actuated by variations in pressure in the pipes 23, 24 and 23 by and in accordance with variations in temperature in the tunnel' through the agency of the thermostatic bulbs 23,

l 21 and 23. Those skilled in the art will appreciate the diagrammatic nature of this part of the disclosure and that many well known forms of automatic temperature regulated mechanism of this type are known. 1

The branches i1, i3 and I3 terminate in the headers 23, 33 and 3|, each of which is provided with a plurality of subsidiary branches individually provided with the control valves 32, 33 and 34. These subsidiary branches terminate in nozzles or Jets 33, as is clear from Figure 3. These nozzles, for example, may consist simply of short lengths of pipe closed at the end and provided with a series of discharge orifices 33, see Figure 3. They are positioned, as shown in Figure 1, along the tube, and through the control action of the valves 32, 33 and 34 steam may be delivered into the tube at any one of a plurality of points to produce desired temperature conditions along the tube.

Connected to the upper end of the'tube I0 is another tube 31 which extends back towards the lower end of tube Ill and is inclined upwardly, as is apparent from-Figure l. Surrounding the ma- Jor portion of the tube 31 is a second tube 33, which tubes together form a jacket into which steam may be introduced to heat the contents of the tube 31. Steam is supplied to this Jacket by means of the branch connection 4| and the quanis connected to the inlet of a pump 43, the outlet of which discharges into a receptacle 1.

The operation of this apparatus to carry out the method of this invention will be explained in connection with a typical example. A cold water mixture of starch, either with or without added enzymes or other converting agents, is prepared in the vat l and the solid particles are maintained in suspension by the continuous rotation of the beater paddles 3. A portion of the vat's contents is discharged into the receptacle 3 until the level is such that valve 9 is closed by the float 6. Motor 3 is running so that the mixing and propelling blades 12 are rotating. This causes-the material to gradually advance to the right, up through tube ii, at a rate depending upon the speed of rotation of the paddles l2, their pitch, and the size of the tube ill with respect thereto. Steam is delivered into the batch through the nozzles 35 connected to the branch n. It'm'ay be assumed, for exa'mpleftha't it'is" time the material reaches the next section of the tube heated by'the nozzles connected to the branch I 8, the temperature of the material will have reached 180, F. The attainment of and maintenance of this temperature is assured by the presence of the bulbs 26 and its control over the valve 20. Let it be assumed that the material then progresses through the next section in the region of the nozzles connected to the branch I 3 while being maintained at a temperature of 180 F. This condition is ensured by the presence of the thermostatic bulb 21 at the end of this section. If it is then desired to rapidly raise the temperature in the third section to 210 F. this is accomplished by the proper setting of valve 23. It will, of course, be apparent that the attainment ,of these temperatures may be arrived at in accordance with other time-temperature curves, depending upon the setting of the valves 20, 2|, 22, 32, 33 and 34. Y

By the time the material reaches the end of the tube l0, it will have attained a consistency or liquefaction such that it will readily be forced through the tubes 31 and 33 where it may be further treated, depending upon the result de.- sired. For example, in passing through the tube 31 the temperature of the material may be controlled either by raising or lowering it by the control of the supply of heating medium to the jacket 38. The processing may be further continued in the tube 39 or, in those cases where the batch has been completely converted in tube 31, or 38, action, particularly in the case where enzymes are employed, may be arrested by supplying a heating medium, such as steam to the Jacket II. The material is then discharged into the tank 41 aided by the presence of the pump 46 An important feature of this invention is that there is provided a continuous method of starch conversion, the rate 'of supply of which may be readily controlled so that the converted starch will be supplied at the rate at which it is used.

By controlling the variable factors which directly ailfect the time-temperature curve of the material under treatment, it is apparent that all manner of conversion methods may be carried out in accordance with practical requirements and continuously.

' that substantially .all of the starch particles are Parts by weight Starch. 25.0

Talc-.. 15.0 -Colored pigment 4.5 Diastatic preparation 0.5 Water 5.0

subjected to uniform treating conditions and the.

temperature throughout the starch suspension at the diiferent stages is. practicallyuniform and.

- arrived at at substantially the same time. The

presence of the blades or paddles l2 ensures a continuous agitation of the mixture while advan'cing it, and the distribution of the large num- 1'07 her-'0!- steam nozzles' a longthe path of travelof the material ensures a rapid and unitorm' heating of any particular batch. 1

It is believed that the advantages of the apcross-section of the paratus and methods of this invention will be emphasized by illustrating with examples the ,wide range of variations in theprocess made possible:

Example of back fllling miirtu re for cotton. cloth For such a mixture the steam controls and the rate of flow of mixture through the machine, are adjusted to raise the temperature thereof to 180- F. in three minutes, then to raise the temperature to 205 F. in six minutes and to maintain that temperature for an additional six minutes. The result of this treatment is a rather viscous, converted starch suitable for example for back sizing or back filling, suitable for the treatment of shade cloth,- carpets and the like. In the conversion of suspensions of such high concentrations the tubes 31 and 3 8 of the-apparatus may be equipped with mechanical conveyors similar to that shown in connection with thetube It in which circumstance it is preferable to eliminate the pump 40.

The following is an example of a sizing material suitable for the surface sizing of paper:

Parts by weight Tapioca flour 10.0 Diastatic preparation 0.1

Water 89.9

adhesive for. laminating or carton sealing:

. Parts by weight Tapioca starch $8.0 Diastatic preparation 2.0 Water 50.0

The final example is that oi: a size for paper:

, Parts by weight Cornstar h 4.0 Diastatic preparation- 0.1

. iWater 95.9

This mixture is heated to 180 n. in three mincooling would be eilfected in the combination comprising an for six minutes and then cooled in six minutes to 130 F. With the apparatus illustrated the tube 39 by supplying cold water to the jacket 40.

An object of inclining the tubes upwardly is to ensure that they will be fllled with the mixture at all times during the operation of the apparatus. In addition it is possible by the introduction of steam, hot water, or therlike-at the high end to clean out the apparatus and drain it out at the drain I.

It is of course apparent to those skilled in the art that the automatic control of the apparatus can be eliminated and the attainment of desired temperaturewlthin the tubes can be accomplished by hand regulation of the valves; Those skilled 'in the art will appreciate that the motor I3 is the available forms of enzymes and is of particular value because of the ability to readily change the time-temperature curve 01 the mate-- rial to accommodate the processto the characteristics of the wide range of enzymes available for these purposes. i

I do not, therefore, desire to be strictly limited to the disclosure as given for purposes of illustration but rather to the scope of the appended claims.

What I claim is:

1. A continuous method of converting starch, including the steps of moving an aqueous fluid mixture 01' starch at a uniform rate through spaced heating stations and applying heat at each station to heat the mixture at these stations to the desired temperatures by injecting steam di-' rectly into the mixture while agitatingit at each of the stations wherein a minimum of starch is converted to sugars.

2. A continuous method of uniformly treating water suspensions oi starch, including the steps of moving a water mixture of starch through a 1 tube at a uniform rate, applying heat to the moving stream by injecting steam thereinto at spaced points in diilerent quantities to raise the temperatures of the stream to; difl'erent values, and continuously agitating the mixture while heating it to insure a uniformapplication of heat throughout the mixture.

3. In an apparatus for converting starch,- the combination comprising an elongated casing, means in said casing for simultaneously advanc-' ing and agitating starch mixtures therealong, and a plurality of individually controlled devices-distributed along said casing for discharging steam into the starch as it advances therethrough.

4. In an apparatus i'orconverting starch, the elongated casing, means in said casing for simultaneouslyadvancing therealong and mixing suspensions of starch,

a plurality of individually controlled nozzle'devices distributed along said casing for discharging steam into the starch as it advances therethrough, and temperature sensitive means controlled by and in accordance with the temperature conditions within the casing for automatically controlling said'nozzle devices.

5. In an apparatus for converting starch in water suspensions, comprising an elongated'casing composed of a plurality of sections connected end to end, means in the first section for conveying the starch therethrough while agitating it, heating means for the first section comprising a plurality of steam nozzles opening directly thereinto, jackets for the other sections having means for supplying heating or cooling fluids to control the temperatures of the materials as they pass through those sections, and means subject to the temperature conditions in the first section for controlling the supply of steam to the nozzles thereof.

6. A continuous method of treating starch to form a homogeneous paste suitable i'or sizing textiles, paper and the like, comprising moving a water suspension of starch and a converting agent along a defined path in a stream while agitating it and uniformly heating the mixture, by injecting steam into it, to difi'erent desired temperatures at spaced regions in its path of travel.

7. A continuous method of treating starch comprising moving a water suspension thereof along a defined path at a uniform speed while agitating it and uniformly heating the mixture to different desired temperatures at spaced regions in itspath of travel by introducing steam directly into the mixture to gelatinize it with a minimum of dextrinization.

8. A continuous method of uniformly treating water suspensions of starch, including the steps of,moving a water mixture of ungebatinized starch through a tube at a uniform rate and injecting steam into the moving stream at spaced regions while agitating it to heat the mixture uniformly to different desired temperatures in those regions and for periods of time suflicient to completely gelatinize it with a formation of minimum amounts of sugar.

ROWLAND A. GALE. 2o 

